A number of approaches are known in the prior art for placing and drilling finger holes in bowling balls. Some of these systems are for the purpose of producing finger holes in one bowling ball which are identical to those of another bowling ball. A representative device of this latter type is that disclosed in U.S. Pat. No. 5,092,054, issued Mar. 3, 1992. The patent discloses an arcuate measuring device for measuring distances along a spherical surface such as a bowling ball. The device includes a curved guide member with measurement marking thereon. A measurement device is slidably retained on the guide member. Removable pins are provided to permit measuring between two finger holes in a bowling ball. An aperture is provided in the measurement device to permit marking a distance on the ball.
.U.S. Pat. No. 4,191,357, issued Mar. 4, 1980, discloses a relatively complex device for duplicating in a new bowling ball the exact size, shape, direction, and span of the finger and thumb holes in an existing, used bowling ball.
A patentability search directed to the current invention also located the following U.S. Pat. Nos.: 3,878,762, issued Apr. 22, 1975, 4,742,620, issued May 10, 1988, 3,429,049, issued Feb. 25, 1969, 4,257,165, issued Mar. 24, 1981, 2,706,338, issued Apr. 19, 1955, 4,242,801, issued Jan. 6, 1981, and 3,161,041, issued Dec. 15, 1964.
The duplication of finger and thumb hole locations, i.e. the transfer of locations from one bowling ball to another, has always been a difficult and time consuming task, often requiring the utilization of complex, expensive equipment. Furthermore, prior art systems often require elaborate measurement and marking techniques as well as precise set up of equipment. Of course, the more complex the procedures and equipment, the greater the likelihood that error will occur resulting in incorrect drilling of a new ball.